The first solution: swap the barrel of the old gun. This design decision lengthens the barrel by 690 mm. The new barrel, combined with an increased charge, provides a muzzle velocity of 515 m/s, with a 6.23 kg shell. According to calculations, at 500 meters, against armour with coefficient 2400 at a 30 degree angle, the shell penetration will be 39 mm, and maximum range 8500 meters. The increased power is possible due to the use of a muzzle brake.
The experimental prototype fired 200 proof and 115 normal shots. The results are satisfactory.
This solution provides immediate production of more powerful regimental guns based on existing guns, as the changes to the production process are insignificant. Furthermore, it is possible to replace the barrels on old regimental guns in the field.
The second solution is to use the blueprints we have already developed and began production of. This prototype has muzzle velocity of 550 m/s, and range of 9500 m. The new gun weighs about 100 kg less than the old one. The rate of fire is increased due to the use of a semi-automatic breech from the regimental gun. This gun is smaller than the old one.
The gun will also be simpler to produce than the old one. The re-barreled old gun and the new gun will use the same shell.
Please advise on urgent government trials of the first prototype of the re-barreled gun."
The "old gun" is the 76.2 mm model 1927 regimental gun. Here is a photograph of the modernized re-barreled gun:
And here is a photograph of another modernized version of the mod. 1927, developed in Leningrad.